Unpleasant somatosensory stimuli such as pain and itch can interrupt normal behavior. But survival can depend on resuming normal behavior before these challenges are fully resolved. The neural mechanisms that prioritize behavior when individuals are challenged with unpleasant somatosensory sensations, however, are not fully understood. Recently, we identified a neural circuit activated by hunger that can inhibit pain, prioritizing food seeking over tending to an injury. Here, we examine the ability of hunger, and neurons activated by hunger, to inhibit behavioral responses to another unpleasant somatosensory sensation – itch. We demonstrate that food deprivation inhibits scratching induced by 3 different pruritogenic stimuli: histamine, serotonin, and chloroquine. The inhibition of scratching correlates with the level of food deprivation, suggesting a cross-competition of alarm systems in the brain whereby more energy need more efficiently inhibits competing drives. Finally, we show that activity in hunger-sensitive, hypothalamic agouti-related protein (AgRP)-expressing neurons is sufficient to inhibit itch. Taken together, we showed that hunger or AgRP neuron activity inhibits itch, demonstrating that organisms have neural systems to filter and process ascending spinal signals activated by unpleasant somatosensory stimuli to prioritize salient needs.

疼痛和瘙痒等令人不愉快的体感刺激会扰乱正常行为。但生存可能取决于在这些挑战得到完全解决之前恢复正常行为。然而，当个体受到不愉快的体感感觉挑战时，优先考虑行为的神经机制尚不完全清楚。最近，我们发现了一种由饥饿激活的神经回路，可以抑制疼痛，优先寻求食物而不是处理伤害。在这里，我们研究了饥饿以及饥饿激活的神经元抑制对另一种令人不快的体感感觉（瘙痒）的行为反应的能力。我们证明，食物匮乏可以抑制由 3 种不同的致痒刺激物（组胺、血清素和氯喹）引起的抓挠。对抓挠的抑制与食物匮乏的程度相关，这表明大脑中的警报系统存在交叉竞争，因此需要更多的能量来更有效地抑制竞争驱动力。最后，我们发现表达饥饿敏感的下丘脑刺鼠相关蛋白（AgRP）神经元的活性足以抑制瘙痒。综上所述，我们发现饥饿或 AgRP 神经元活动可以抑制瘙痒，这表明生物体具有过滤和处理由不愉快的体感刺激激活的上行脊髓信号的神经系统，以优先考虑突出的需求。